From Merrill Lynch economist David Rosenberg:

In the USA, companies are spending a mere 5% of their cash flow on
wages/supplements and the trend is going down, which is indicative of a market that retains slack. In the late 1990s, the Fed was correct in raising rates as it became clear as the jobless rate moved to and below 4% that wage pressures were accelerating and this is seen by the ever-rising share of corporate profits being devoted to labor income. This has not happened this cycle.... You have to go back to 1929 to find a business cycle – and the one we are in is four years old now – in which the wage and salary share was as low as it is today this far into an expansion. Bloomberg News quotes the legendary Nobel-prize winning economist Robert Solow as saying that an economy that generates productivity gains which see those gains concentrated only at the corporate level is an economy that is actually “performing poorly”.